Among the threats facing the National Security Agency are Al Qaeda, the Iraqi insurgency, and eBay.

Yes, eBay, the online auction house. Not because its members sell state secrets, but because of a company that eBay purchased last year — Skype.

Skype is an online service that lets people converse through their computers. Its 75 million users place voice calls over the Internet. The calls sound clear. They’re free, because phone carriers aren’t used. And because of the Internet’s diffused architecture and its facility for privacy, Skypesters’ identities, their locations, and the substance of their conversations can be undetectable. This is not what the NSA’s worldwide eavesdroppers want to hear.

Skype and other widely used Internet communications devices, including e-mail, threaten the NSA’s ability to gather intelligence and to do so legally. For more than four years, without warrants and by order of President Bush, the agency has hunted for terrorists by intercepting communications between people in the United States and people abroad possibly connected to terrorism.

The legality of that order is being hotly debated in Congress. Bush says that the 27-year-old Foreign Intelligence Surveillance Act, which governs domestic eavesdropping for intelligence purposes, doesn’t adequately address Internet-based communications.

The article goes on to examine the legal and practical conundrums of surveillance in a world of Internet-based communications: FISA’s narrow focus makes it difficult to apply to the tracking of packet-based data, but broader search methods amount to “taking the haystack” in a way that could pose a threat to civil liberties. The article quotes extensively from a new law journal piece by Kim Taipale, entitled “Whispering Wires and Warrantless Wiretaps: Data Mining and Foreign Intelligence Surveillance,” which is also worth reading.

How long will it take before even the Federal Communications Act of 1934 is amended to bring it into the modern era and deal with emergency and other situations. Part of the largesse bestowed on the telecommications industry in the form of deregulation and spectrum sales could have resulted in a safer more redundant more interoperable communication system with protections against abuse. But the free market reigned! Let’s hope that reign does not turn into the rain of terrorist attacks.